Wireless USB is a short-range wireless radio communication protocol. It was designed to operate in the 2.0 to 10.6 GHz frequency range. Wireless USB may be used for wireless communication between a computer and computer peripheral devices such as mice, keyboards, printers and scanners, as well as for communicating with game controllers, digital cameras, portable media players, hard disk drives and flash drives.
Other commercial wireless transceivers for providing wireless communication between a computer and peripheral devices use other standards such as Firewire (IEEE 1394) and the mini-USB standard. These other standards use a form factor with a different plug size.
A “nano” dongle is a USB dongle of a particular form factor in which the end cap protrudes beyond the socket surface by about 6.8 mm. A “pico” dongle is a USB dongle of a particular form factor in which the end cap protrudes beyond the socket surface by an amount less than a nano dongle. Thus, the length of the pico dongle end cap is less than the length of a nano dongle. A pico dongle form factor is desirable because it is convenient to leave the dongle plugged into a laptop or other mobile computing device rather than inserting the dongle before each use and removing the dongle before transporting the mobile computing device. Having the endcap of a dongle almost flush with the edge of a mobile computing device reduces the likelihood that the dongle may be damaged while the mobile computing device is in transit. However, creating a small dongle that has a sufficient radiation pattern and power may be a challenge. The size of a dongle limits the size of the electronics that may be used, especially the size of the antenna, which typically affects the radiation pattern. Thus, an improved antenna design is sought.